Organic & Biomolecular Chemistry,
Год журнала:
2023,
Номер
21(46), С. 9275 - 9285
Опубликована: Янв. 1, 2023
Molecular-iodine
catalyzed
access
to
an
important
class
of
bio-relevant
indole
derivatives,
cyclopenta[b]indoles,
has
been
achieved
via
a
cascade
addition/intramolecular
cyclization
reaction
indoles
and
acetone.
Explorations
diverse
substitution
patterns
revealed
essential
substrate-control
in
the
reaction.
The
high-density
electronic
core
is
pivotal
favouring
formation
indolyl-cyclopenta[b]indole
derivatives;
contrast,
electron
deficiency
hindered
process,
directing
bis(indolyl)propanes.
Investigations
on
mechanistic
pathway
that
bis(indolyl)alkanes
were
intermediates
for
addition-cyclization
process.
This
simple
experimental
method
provides
sustainable
synthetic
cyclopentannulated
indoles.
Chemistry - A European Journal,
Год журнала:
2024,
Номер
30(34)
Опубликована: Апрель 16, 2024
Cyclohepta[b]indoles,
prevalent
in
natural
products
and
pharmaceuticals,
are
conventionally
accessed
via
metal
or
Lewis
acid-mediated
cycloadditions
with
prefunctionalized
substrates.
Our
study
introduces
an
innovative
sequential
catalytic
assembly
for
synthesizing
cyclohepta[b]indoles
from
readily
available
isatin
derivatives.
The
process
involves
three
sequences:
ring-closing
metathesis,
hydrogenation,
acid-catalyzed
ring
expansion.
RCM
of
2,2-dialkene-3-oxindoles,
formed
by
butenyl
Grignard
addition
to
3-allyl-3-hydroxy-2-oxindoles,
yields
versatile
spirocyclohexene-3-oxindole
These
derivatives
undergo
further
transformations,
including
dibromination,
dihydroxylation,
epoxidation,
Wacker
oxidation
at
the
double
bond.
Hydrogenation
spirocyclohexane-3-oxindoles.
Their
subsequent
expansion/aromatization,
dependent
on
acid
catalyst,
results
either
cyclohepta[b]indole-indoline
conjugates,
adding
a
unique
synthetic
dimension.
utility
this
methodology
is
exemplified
through
synthesis
A-FABP
inhibitor,
showcasing
its
potential
pharmaceutical
applications.
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 16, 2024
A
novel
asymmetric
(4
+
3)
cycloaddition
of
indole-2,3-quinodimethanes
in
situ
generated
from
3-methyl-2-indolylmethanols
with
3-indolylmethanols
via
chiral
phosphoric
acid
catalysis
has
been
established.
The
reaction
exhibits
a
broad
substrate
scope
affording
the
diverse
enantioenriched
cyclohepta
fused
diindoles
high
yields
good
enantioselectivities.
Significantly,
this
work
represents
first
application
as
4C
synthons
instead
commonly
reported
three-atom
reactions.
Organic reactions,
Год журнала:
2024,
Номер
unknown, С. 1 - 410
Опубликована: Окт. 29, 2024
The
reaction
of
allylic
cations
with
1,3‐dienes
is
formally
equivalent
to
the
Diels–Alder
but
leads
seven‐membered
rings.
An
cation
contains
2
pi
electrons,
and
thus
precisely
analogous
an
alkene
and,
like
latter,
can
function
as
a
dienophile.
substituent
at
central
carbon
serves
terminate
reaction.
Most
often,
this
oxyanion
or
silyl
ether,
other
groups
have
been
used.
These
(4+3)
cycloadditions
proceed
via
mechanisms
that
range
from
stepwise
concerted.
Diastereoselectivity,
regioselectivity,
enantioselectivity
all
achieved,
though
there
are
still
opportunities
for
development
new
reactions
in
area.
Asymmetric
catalysis
enzymatic
such
its
infancy.
More
recent
advances
center
on
related
benzylic
involve
electron
rich
heterocycles
furans,
indoles,
thiophenes
structures.
This
chapter
covers
1997
2017,
supplemental
references
added
bring
work
up
date
through
2023.
It
illustrates
both
growth
technical
progress
theoretical
understanding
during
time.
Organic & Biomolecular Chemistry,
Год журнала:
2023,
Номер
21(46), С. 9275 - 9285
Опубликована: Янв. 1, 2023
Molecular-iodine
catalyzed
access
to
an
important
class
of
bio-relevant
indole
derivatives,
cyclopenta[b]indoles,
has
been
achieved
via
a
cascade
addition/intramolecular
cyclization
reaction
indoles
and
acetone.
Explorations
diverse
substitution
patterns
revealed
essential
substrate-control
in
the
reaction.
The
high-density
electronic
core
is
pivotal
favouring
formation
indolyl-cyclopenta[b]indole
derivatives;
contrast,
electron
deficiency
hindered
process,
directing
bis(indolyl)propanes.
Investigations
on
mechanistic
pathway
that
bis(indolyl)alkanes
were
intermediates
for
addition-cyclization
process.
This
simple
experimental
method
provides
sustainable
synthetic
cyclopentannulated
indoles.
